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Multi‐band‐ and in‐plane‐accelerated diffusion MRI enabled by model‐based deep learning in q‐space and its extension to learning in the spherical harmonic domain
Author(s) -
Mani Merry,
Yang Baolian,
Bathla Girish,
Magnotta Vincent,
Jacob Mathews
Publication year - 2022
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.29095
Subject(s) - aliasing , acceleration , computer science , spherical harmonics , algorithm , artificial intelligence , image resolution , physics , mathematics , mathematical analysis , undersampling , classical mechanics
Purpose To propose a new method for the recovery of combined in‐plane‐ and multi‐band (MB)‐accelerated diffusion MRI data. Methods Combining MB acceleration with in‐plane acceleration is crucial to improve the time efficiency of high (angular and spatial) resolution diffusion scans. However, as the MB factor and in‐plane acceleration increase, the reconstruction becomes challenging due to the heavy aliasing. The new reconstruction utilizes an additional q‐space prior to constrain the recovery, which is derived from the previously proposed qModeL framework. Specifically, the qModeL prior provides a pre‐learned representation of the diffusion signal space to which the measured data belongs. We show that the pre‐learned q‐space prior along with a model‐based iterative reconstruction that accommodate multi‐band unaliasing, can efficiently reconstruct the in‐plane‐ and MB‐accelerated data. The power of joint reconstruction is maximally utilized by using an incoherent under‐sampling pattern in the k‐q domain. We tested the proposed method on single‐ and multi‐shell data, with high/low angular resolution, high/low spatial resolution, healthy/abnormal tissues, and 3T/7T field strengths. Furthermore, the learning is extended to the spherical harmonic basis, to provide a rotational invariant learning framework. Results The qModeL joint reconstruction is shown to simultaneously unalias and jointly recover DWIs with reasonable accuracy in all the cases studied. The reconstruction error from 18‐fold accelerated multi‐shell datasets was <3%. The microstructural maps derived from the accelerated acquisitions also exhibit reasonable accuracy for both healthy and abnormal tissues. The deep learning (DL)‐enabled reconstructions are comparable to those derived using traditional methods. Conclusion qModeL enables the joint recovery of combined in‐plane‐ and MB‐accelerated dMRI utilizing DL.